Only a limited number of studies have examined how medical and health care decisions are made; even fewer have dealt with the decision making process as regards the treatment of cancer. The importance of this issue is underscored by the uncertainty of prognosis and treatment outcome. Effective, satisfactory treatment is difficult if the factors affecting the decision making process of patient and physician remain unclear. The significance of this problem is seen in the expanding field of psychosocial oncology. Because breast cancer is a chronic disease, treatment decisions exist as a continuum over a relatively long time period. The 'natural history' of the decision process will vary including opting for no further therapy. This study will follow 120 patients at the Johns Hopkins Oncology Center diagnosed with primary breast cancer who are eligible/recommended for chemotherapy. Patients will be entered into the study after surgery but at the point where chemotherapy will be offered to them as a treatment option. This will necessitate examining some of the factors (independent variables) which are hypothesized to affect patient decisions retrospectively, while other factors will be examined prospectively. The study will examine two outcome measures: 1) the acceptance of a chemotherapy clinical trial vs nonacceptance of a clinical trial; 2) acceptance of chemotherapy vs nonacceptance of chemotherapy. Drawing from behavioral decision theory it is expected that factors other than the patient's disease characteristics will significantly affect the decision process. Factors that are expected to affect the decision process are risk taking, physician framing, sunk costs, and patient framing. To evaluate these factors, patients will be interviewed at the time of their meeting with a JHH oncologist immediately following surgery. Patient's disease characteristics will be collected directly from the physician through the use of a short self-administered questionnaire. The patient-physician interaction will also be directly observed and patient records will be reviewed within two months to confirm the treatment decision. Patients whose records are incomplete will be contacted directly.